1. The Field of the Invention
The present invention is related to a brine shrimp egg harvesting device. More particularly, the present invention is directed to a brine shrimp egg harvesting device which efficiently harvests brine shrimp eggs while causing only minimal disturbance to the surface of the water in which the eggs float.
2. Technical Background
Brine shrimp are primitive crustaceans which normally inhabit bodies of water having high saline contents such as the Great Salt Lake in Utah. They serve as a source of food for many fish. Brine shrimp eggs are remarkable in that they can be dried, stored, and hatched years later by returning them to salt water. The ability to stockpile dried brine shrimp eggs for future hatching makes commercial harvesting of the eggs a profitable venture.
Brine shrimp and their eggs conglomerate in floating colonies at the surface of the water. Brine shrimp colonies typically occupy the top quarter-inch of water. The eggs are extremely small in size, such that an ounce of water may contain several million eggs. This floating layer is eventually carried by the wind and the tide to the shore.
Prior harvesting approaches have focused on collection after the eggs had been deposited on the shore. Nets or shovels were used to scoop up the thin layer of shrimp eggs and place them into storage containers. This approach was far from effective, however, as the harvester had to depend on the wind and the tide to bring the eggs ashore. Thus, the harvester had no control over when or where the eggs would be deposited.
To deal with the problem of unpredictability, elaborate fencing structures were erected, extending outwardly from the shoreline, to direct incoming shrimp colonies to preselected harvesting sites on the beach. While noticeably more effective in concentrating colonies at predetermined sites, this method was not, however, without its disadvantages. As an initial problem, these extensive fencing structures were understandably expensive. Additionally, this method required that the harvester have access to large areas of shoreline. Finally, the harvester still, had to wait for the right wind and tide conditions to bring the shrimp eggs ashore.
Because of the disadvantages inherent in shoreline harvesting methods, increasing attention has been directed toward methods for harvesting brine shrimp eggs directly from the water. Such methods usually employ a boat or raft equipped with a collection device.
Previous attempts to harvest brine shrimp eggs directly from the water have utilized an assortment of nets or screening devices to skim the eggs from the surface of the body of water. The collected eggs were then transferred from the nets or screens and into storage containers. U.S. Pat. No. 3,768,193 by London and U.S. Pat. No. 5,042,187 by Bentzley are two examples of prior art devices which utilize a netting device to collect brine shrimp eggs from a water surface.
There are a number of problems, however, with devices employing netting or screening procedures to remove brine shrimp eggs from water. As an initial matter, netting or screening is generally inefficient because of the very small size of the eggs. With a concentration typically of several million eggs in a single ounce of water, one can easily imagine how great numbers of the eggs pass through conventional net systems avoiding capture. As the netting or screening device becomes finer and finer, to increase the extraction efficiency of brine shrimp eggs from the water, additional problems arise. It has been found that eggs cling together and solidify when concentrated, thereby becoming very difficult to remove from the netting.
Because of the problems inherent in extracting brine shrimp eggs by netting procedures, attempts have been made to scoop up the top layer of water containing the brine shrimp eggs using a conveyor belt system. U.S. Pat. No. 5,042,187 by Bentzley discloses one such method for harvesting brine shrimp eggs. In Bentzley, a conveyor belt is fitted with a plurality of net-fitted frames. The belt system is angled with a low end in the water adjacent the concentrated brine shrimp eggs and a high end out of the water over a collection bin. The belt system rotates the frames such that the frames enter the water underneath the belt system, traveling toward the oncoming brine shrimp eggs. As the netted frames round the low end, they lift a sample of brine shrimp eggs and water. Once the frames round the high end, the brine shrimp eggs fall out of the netting into the collection bin. One difficulty with the Bentzley device is the same with most brine shrimp egg netting devices; once a portion of the water drains out of the netting the eggs have a tendency to conglomerate making it difficult to remove them from the netting.
Another problem with the Bentzley device is the disturbance and agitation of the brine shrimp eggs during harvesting. If the method of harvesting disperses or causes the colony of brine shrimp eggs to sink the harvest will be less efficient. Water disturbance results in part from the direction of the netted frames around the belt system. Disturbance also results when the device used for gathering up a portion of brine shrimp eggs has flat surfaces that splash into the water.
In the Bentzley device, the concentration mechanism causes brine shrimp to flow towards the conveyor belt affixed with the netted frames. The netted frames rotate about the conveyor belt in a direction which causes the brine shrimp eggs and water to flow in the opposite direction as the flow established by the concentration mechanism. As these flows collide at the surface of the water, brine shrimp eggs floating at the point of collision are dispersed and forced below the water surface. This negatively affects the efficiency of the harvesting operation.
Conventional conveyor systems are sometimes affixed with paddles which guide a quantity of brine shrimp eggs into a collection device. The flat surface area of the paddle tends to splash down onto the water as opposed to gradually knifing through it. When flat surfaces enter the brine shrimp colony, the disturbance in maximized. This disturbance in the brine shrimp colony negatively affects the efficiency with which the brine shrimp eggs are removed from the water.
It will be appreciated, that it would be an advancement in the art to provide a brine shrimp egg harvester which could extract a sample of brine shrimp eggs and water from the water surface, without disturbing the flow of brine shrimp eggs into the device. It would be a further advancement in the art to provide a brine shrimp egg harvester which can extract a relatively uniform ratio of eggs to water to allow for a pumpable slurry. Finally, it would be another advancement in the art to provide a device that performs these functions in an efficient, cost-effective, commercial manner.
Such a brine shrimp egg harvester is disclosed and claimed herein.